Lens.



VSanting.

y*UNITED STATES PATENTOFFIGE. EDWARD A. TRAPP, OF NEW YORK, N. Y

LENS- Specification of Letters Patent.

Patented oct. 17', 190e.

Application led November 7, 1904. Serial No. 231 677. I

To (1.5.7, whom it may concern:

Be it known that I, EDWARD A. TRAPP, a citizen of the United States, and a resident of New York city, in the county of- New York .3 andState of New York, have invented certain new and useful Improvements in Lenses, of

which the following is a specification.

The invention relates to 'improvements in lenses for optical instruments-such as telescopes, opera-glasses, cameras, and the likeand pertains to a novel form or construction of objective or collecting lens for use in such instruments.

The purpose of my invention is to provide an efficient objective-lens of novel form and in one integral piece and capable of being manufactured at the minimum trouble and expense; and my invention consists in what I designate a double cylindrical concave lens, the cylind rica] concavties extending entirely across the opposite faces of the lens and preferably at right angles to each other. When the aforesaid cylindrical concavities extend at a right angle to each other, the image will be refracted in proper relative proportions; but if I should desire to produce a distorted image or refraction-such, for' instance, as a freak picture-1 would run the said concavities'across the opposite faces of the lens atan The invention is' illustrated in the accompanying drawings, in whchl Figurel is an edge view of a lens embodying my invention. Fig. 2 is a top view of same. Fig. 3 is a bottom' View of same. Fig. 4 is a perspective view ofl a lens of rectangular outline and also embodying my invention, and Fig. 5 is a perspective view of'a lens for reflecting an image in distorted or freak form. The preferredform of the lens-is shown in Figs. 1 2, and 3, in which the lens (designated by the numeral 10) is shown as of circularedge outline and having equal cylind ricalcon.- cave opposite faces, the concavities (numbered 11 12, respectively) extending entirely across the opposite faces of the lens and at a right angle to each other and the lens being in one integral piece.

I have discovered that a lens of the character just described will eiliciently perform angle other than a right angleto each other..

the duties of an objective-lens, and aside from its efficiency and other characteristics I regard the lens as important in view of its cheapness of manufacture, the ease with which the lens may be made true with the center lines 'of the concaves crossing each other at right angles, the fact that the images are refracted in proper relative proportions and without distortion, and the further fact that the 'rays passing through the lens extend at right angles to the face of the lens.

Fig. 4 is presented to indicate that the lens may be of polygonal instead of circular out-l line, with the concavities 11 12 extending across the same and at a right angle to each other. The fiat edge surfaces 15 (shown on the lens presented in Fig. 4) are left to re- .'ceive the means by which the lensmay be mounted in an instrument, it beingA intended that themounting means shall cover said surfaces l5. y

In Fig. 5 I illustrate a lens in which the concave surfaces 11 12 do not extend at a right angle to each other and which would onlybe useful in refracting an image in distorted or freak form.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The lens having cylindrical concave opposite faces, the concavities extending at an angle to each other; substantially as set forth.

2. The lens having cylindrical concave opposite faces, the concavities being equal and extending at a right angle to each other; substantially as set forth.`

3. The lens having cylindrical concave 0pposite faces, the concavities being equal and extending at an angle to eachother; substan- EDWARD A. TRAPP. Witnesses: 1

Unas. C. Gum,

AaTHUR MARioN. 

